Accounts Department not fulfilling request

I have phoned the Customer care department twice to request that my outstanding balance be split over 36 months. I bought online, and the option was not provided to buy over 36 months. I called the week after I bought for the first time. When I got my bill, it was not moved to 36 months. I paid the full amount. I then called, and again requested for the amount to be moved to 36 months. I have now reviewed my bill for this month, and AGAIN, the amount has not been moved to 36 months. This is really appalling. As a paying customer who wishes to remain in good standing with Game, I find this really frustrating and upsetting.